What does it mean if Windows isn't supported?

An unsupported version of Windows will no longer receive software updates from Windows Update. These include security updates that can help protect your PC from harmful viruses, spyware, and other malicious software, which can steal your personal information. Windows Update also installs the latest software updates to improve the reliability of Windows—new drivers for your hardware and more.

Support end dates

Here are the dates when support will end for PCs running Windows XP and Windows Vista without the latest service packs: